/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.runners.gaia.translation.types;



import com.bff.gaia.unified.sdk.coders.Coder;

import com.bff.gaia.unified.sdk.util.CoderUtils;

import com.bff.gaia.unified.sdk.util.WindowedValue;

import com.bff.gaia.unified.sdk.values.KV;

import com.bff.gaia.api.common.typeinfo.TypeInformation;

import com.bff.gaia.api.java.functions.KeySelector;

import com.bff.gaia.api.java.typeutils.ResultTypeQueryable;



/**

 * {@link KeySelector} that extracts the key from a {@link KV} and returns it in encoded form as a

 * {@code byte} array.

 */

public class KvKeySelector<InputT, K>

    implements KeySelector<WindowedValue<KV<K, InputT>>, byte[]>, ResultTypeQueryable<byte[]> {



  private final Coder<K> keyCoder;



  public KvKeySelector(Coder<K> keyCoder) {

    this.keyCoder = keyCoder;

  }



  @Override

  public byte[] getKey(WindowedValue<KV<K, InputT>> value) throws Exception {

    return CoderUtils.encodeToByteArray(keyCoder, value.getValue().getKey());

  }



  @Override

  public TypeInformation<byte[]> getProducedType() {

    return new EncodedValueTypeInformation();

  }

}